The Inter-Mammary Sticky Roll: A Novel Technique for Securing a Doppler Ultrasonic Probe to the Precordium for Venous Air Embolism Detection.

Venous air embolism is a devastating and potentially life-threatening complication that can occur during neurosurgical procedures. We report the development and use of the "inter-mammary sticky roll," a technique to reliably secure a precordial Doppler ultrasonic probe to the chest wall during neurosurgical cases that require lateral decubitus positioning. We have found that this noninvasive technique is safe, and effectively facilitates a constant Doppler signal with no additional risk to the patient

The ideological divide in confidence in science and participation in medical research

Abstract In the United States, the wide ideological divergence in public confidence in science poses a potentially significant problem for the scientific enterprise. We examine the behavioral consequences of this ideological divide for Americans’ contributions to medical research. Based on a mass survey of American adults, we find that engagement in a wide range of medical research activities is a function of a latent propensity to participate. The propensity is systematically higher among liberals than among conservatives. A substantial part of this ideological divide is due to conservative Americans’ lower confidence in science. These findings raise important issues for the recruitment of subjects for medical studies and the generalizability of results from such studies

A real-time analysis of GFP unfolding by the AAA+ unfoldase PAN

Protein quality control systems are essential to maintain a healthy proteome. They often consist of an unfoldase unit, typically an AAA+ ATPase, coupled with a protease unit. In all kingdoms of life, they function to eliminate misfolded proteins, and thus prevent that their aggregates do harm to the cell, and to rapidly regulate protein levels in the presence of environmental changes. Despite the huge progress made in the past two decades in understanding the mechanism of function of protein degradation systems, the fate of the substrate during the unfolding and proteolytic processes remains poorly understood. Here we exploit an NMR-based approach to monitor GFP processing by the archaeal PAN unfoldase and the PAN–20S degradation system in real time. We find that PAN-dependent unfolding of GFP does not involve the release of partially-folded GFP molecules resulting from futile unfolding attempts. In contrast, once stably engaged with PAN, GFP molecules are efficiently transferred to the proteolytic chamber of the 20S subunit, despite the only weak affinity of PAN for the 20S subunit in the absence of substrate. This is essential to guarantee that unfolded but not proteolyzed proteins are not released into solution, where they would form toxic aggregates. The results of our studies are in good agreement with previous results derived from real-time small-angle-neutron-scattering experiments and have the advantage of allowing the investigation of substrates and products at amino-acid resolution

An NMR Study of a 300-kDa AAA+ Unfoldase

AAA+ ATPases are ubiquitous hexameric unfoldases acting in cellular protein quality control. In complex with proteases, they form protein degradation machinery (the proteasome) in both archaea and eukaryotes. Here, we use solution-state NMR spectroscopy to determine the symmetry properties of the archaeal PAN AAA+ unfoldase and gain insights into its functional mechanism. PAN consists of three folded domains: the coiled-coil (CC), OB and ATPase domains. We find that full-length PAN assembles into a hexamer with C2 symmetry, and that this symmetry extends over the CC, OB and ATPase domains. The NMR data, collected in the absence of substrate, are incompatible with the spiral staircase structure observed in electron-microscopy studies of archaeal PAN in the presence of substrate and in electron-microscopy studies of eukaryotic unfoldases both in the presence and in the absence of substrate. Based on the C2 symmetry revealed by NMR spectroscopy in solution, we propose that archaeal ATPases are flexible enzymes, which can adopt distinct conformations in different conditions. This study reaffirms the importance of studying dynamic systems in solution

Small RNA pathway genes identified by patterns of phylogenetic conservation and divergence

Genetic and biochemical analyses of RNA interference (RNAi) and microRNA (miRNA) pathways have revealed proteins such as Argonaute/PIWI and Dicer that process and present small RNAs to their targets. Well validated small RNA pathway cofactors, such as the Argonaute/PIWI proteins show distinctive patterns of conservation or divergence in particular animal, plant, fungal, and protist species. We compared 86 divergent eukaryotic genome sequences to discern sets of proteins that show similar phylogenetic profiles with known small RNA cofactors. A large set of additional candidate small RNA cofactors have emerged from functional genomic screens for defects in miRNA- or siRNA-mediated repression in C. elegans and D. melanogaster1,2 and from proteomic analyses of proteins co-purifying with validated small RNA pathway proteins3,4. The phylogenetic profiles of many of these candidate small RNA pathway proteins are similar to those of known small RNA cofactor proteins. We used a Bayesian approach to integrate the phylogenetic profile analysis with predictions from diverse transcriptional coregulation and proteome interaction datasets to assign a probability for each protein for a role in a small RNA pathway. Testing high-confidence candidates from this analysis for defects in RNAi silencing, we found that about half of the predicted small RNA cofactors are required for RNAi silencing. Many of the newly identified small RNA pathway proteins are orthologues of proteins implicated in RNA splicing. In support of a deep connection between the mechanism of RNA splicing and small RNA-mediated gene silencing, the presence of the Argonaute proteins and other small RNA components in the many species analysed strongly correlates with the number of introns in that species